1. Field of the Invention.
The present invention relates to the field of acoustic coupled data communication devices.
2. Prior Art.
Data communication devices for communicating over telephone lines are well known in the prior art, such devices generally being referred to as modems or modulator/demodulator sets. Such devices, when transmitting, generally receive a serial digital data stream as an electrical input, convert the digital data stream to some form of signal modulared by the data stream so that the modulated signal is within the expected band pass of the telephone system, and couple the modulated signal to the telephone line for transmission to tne desired receiving device. Reception of course involves the reverse process of receiving the modulated signal coming over the phone line and demodulating the signal to recover the digital data stream. In recent years, modems may be directly coupled to the telephone line, provided such equipment is properly certified, which, together with the modular connectors now being used, frequently makes modem connection to the phone line a very easy task. However, in some cases, particularly in the case of portable equipment, acoustic coupling between the modem and the telephone handset may still be required, as not all phone equipment now has or will have modular connectors, either at the phone line itself or at the handset line.
As integrated circuit technology continues to progress, various electronic equipment such as modems and even many portable terminals can readily be packaged in very small sizes so as to conveniently fit into a shirt pocket, coat pocket or the like. While speakers and microphones may also be made very small, acoustic couplers themselves generally have not been made small because of the underlying physical constraints dictated by the fact that the speaker and microphone in an ordinary telephone handset are separated by approximately six inches (center line to center line) so that most acoustic couplers are on the order of eight inches long, clearly not a convenient shirt pocket size. Further, since there is some variation in the separation and angularity between the mouth piece and earpiece in telephone handsets, acoustic couplers heretofore frequently used relatively large and flexible coupling muffs, and even slideable and/or rotatable muffs to accommodate for such variations. By way of example, in U.S. Pat. No. 3,657,479 an acoustic coupler is disclosed wherein each of the muffs is supported on an axis so as to be rotatable to varying angles as required by a telephone handset, with one of the muffs further being supported so as to be slideable to provide different separations between the muffs. U.S. Pat. No. 4,158,106 discloses a telephone handset acoustic coupling cup wherein each of two such cups are eccentrically rotatably mounted on a case so that the cup openings may be varied in distance from one another by rotating the cups with respect to the case.
In U.S. Pat. No. 4,162,373, a flexible acoustic coupler is disclosed wherein the body member between the two muffs or coupling cups is flexible to allow the appropriate angularity between muffs to mate with a handset, and to further allow the folding of the acoustic coupler in half wben not in use, though even when so folded the coupler is far too large for a shirt or a coat pocket. In U.S. Pat. No. 4,268,721 a portable telephone communication device for the hearing impaired is disclosed, characterized by a pair of body members, each carrying a speaker or microphone, with the two body members being hinged together at the center thereof to allow the required angularity between the body members. The hinge is configured to allow some variation in the separation between the two body members, though the hinge motion is quite limited and the entire device is again relatively large and inappropriate for pocket carrying. Finally, U.S. Pat. No. 4,252,996 discloses individual telephone coupling devices which would be used in pairs to provide both mouthpiece and earpiece coupling. While these couplers are smaller than other couplers, they are separate units except perhaps for electrical connection, as opposed to being a convenient integrated package, are still larger than pocket size and are not really suitable for packaging anything other than or beyond the required coupling speaker and microphone.